Cutoff Simulation: Approval Tăng Thì Risk Và Profit Đổi Thế Nào

Điểm cần nhớ

• Cutoff không phải ngưỡng kỹ thuật; nó là nơi growth target, risk appetite và portfolio economics va vào nhau.
• Với PD model, nới cutoff nghĩa là approve thêm một marginal group cụ thể, không phải làm cả portfolio xấu đều nhau.
• Portfolio average có thể đẹp trong khi marginal group lỗ.
• Expected loss nên dùng calibrated PD hoặc observed bad rate đã mature.
• Recommendation tốt thường là nới có chọn lọc theo segment/channel, kèm guardrail và rollback trigger.

A cutoff is a business decision

A cutoff looks like a model threshold, but it is really a decision about how much growth the lender is willing to buy at what risk and economics.

For a PD model, relaxing the rule from PD <= 5% to PD <= 7.5% adds the marginal group 5% < PD <= 7.5%. This group should drive the decision.

The marginal group matters

The combined portfolio can still look acceptable while the marginal group loses money. That is why cutoff simulation should include approval, bad rate, expected loss, revenue, profit and segment/channel mix.

Practical takeaway

A good recommendation is rarely “lower the cutoff everywhere”. It should specify which segments to approve, which channels to exclude, how to adjust limit/pricing, and which early delinquency guardrails to monitor.